描述 The LMX2531 is a low-power, high-performance frequency synthesizer system which includes a fully integrated delta-sigma PLL and VCO with fully integrated tank circuit. The third and fourth poles are also integrated and adjustable. Ultra-low noise and high-precision LDOs are integrated for the PLL and VCO, which yield higher supply-noise immunity and more consistent performance. When combined with a high-quality reference oscillator, the LMX2531 device generates very stable, low-noise local-oscillator signals for up and down conversion in wireless communication devices. The LMX2531 device is a monolithic integrated circuit, fabricated in an advanced BiCMOS process. Several different versions of this product accommodate different frequency bands.特性Multiple Frequency Options Available See Device Information Table Frequencies From: 553 MHz to 3132 MHz PLL Features Fractional-N Delta-Sigma Modulator Order Programmable up to Fourth Order FastLock/Cycle Slip Reduction with Timeout Counter Partially Integrated, Adjustable Loop Filter Very Low Phase Noise and Spurs VCO Features Integrated Tank Inductor Low Phase Noise Other Features 2.8-V to 3.2-V Operation Low Operating Current Low Power-Down Current 1.8-V MICROWIRE Support36-Pin 6-mm × 6-mm × 0.8-mm WQFN Package